Am. J. Respir. Cell Mol. Biol.,
Volume 26, Number 2, February, 2002 216-223
Pseudomonas aeruginosa and Tumor Necrosis Factor-
Attenuate Clara
Cell Secretory Protein Promoter Function
Kevin S.
Harrod
and
Richard J.
Jaramillo
Lovelace Respiratory Research Institute, Asthma and Pulmonary Immunology Program, Albuquerque, New Mexico
The Clara cell secretory protein (CCSP, also CC-10/uterglobin)
is a 16-kD homodimeric protein abundantly expressed in the airways of mammals. Although the molecular function is unknown, gene-targeting studies indicate CCSP as a regulator of
lung inflammation following acute respiratory infection or injury. CCSP is decreased in the lungs of mice following acute
Pseudomonas aeruginosa (P.a.) infection. In the present study,
the role of decreased promoter function in the regulation of
CCSP by P.a. was assessed using an in vitro co-culture system
and in vivo studies of transgenic mice. CCSP promoter activity
in lung epithelial cells was markedly decreased by P.a. or tumor necrosis factor-
(TNF-) in a dose-dependent manner.
Regulation of CCSP promoter function by either P.a. or TNF-
was localized to the proximal 166 bp flanking region of the
CCSP promoter activity. Decreased regulation of the CCSP
promoter by P.a. or TNF- was specific to CCSP, as human surfactant protein D (SP-D) promoter activity was unaffected or
increased by P.a. or TNF-, respectively. A neutralizing antibody against human TNF- was able to reverse both the TNF--
mediated as well as P.a.-mediated decrease in CCSP promoter
function in lung epithelial cells. TNF- secretion by lung epithelial cells coincided with the decrease in CCSP promoter
function following P.a. administration. Using a transgenic
mouse model, P.a. administration to the lung markedly attenuated CCSP promoter-conferred gene expression in vivo. The
attenuation of CCSP promoter activity in lung epithelial cells
by P.a. involves, in part, autocrine/paracrine secretion of TNF-,
which in turn regulates CCSP transcription through cis-active elements in the proximal promoter region.
Abbreviations: aquaporin-5, AQP-5; 
-galactosidase, -Gal; Clara cell
secretory protein, CCSP; CAATT-enhancer-binding protein, C/EBP; colony-forming units, cfu; cytomegalovirus, CMV; lipopolysaccharide, LPS;
luciferase gene, luc; Pseudomonas aeruginosa, P.a.; reverse transcriptase-
polymerase chain reaction, RT-PCR; reverse tetracycline transactivator,
rtTa; surfactant protein, SP; tumor necrosis factor-, TNF-; thyroid transcription factor-1, TTF-1.
